Loughborough University
Leicestershire, UK
LE11 3TU
+44 (0)1509 222222
Loughborough University

Centre for Innovative and Collaborative Construction Engineering


Dr David Baxter


Innovation in the design of continuous flight auger and bored displacements piles

Project Title

Innovation in the Design of Continuous Flight Auger and Bored Displacement Piles


Rock and Alluvium


Dr N Dixon
Dr P R Fleming

Mr S P Hadley
Mr K Cromwell

Director of Research:
Professor K Shiono

Research Period

2004 - 2009

Innovation in the Design of Continuous Flight Auger and Bored Displacement Piles

Proof of alpha values for CFA piles in various types of clay

The value of the soil softening factor used in routine pile design for clay soils is an area of much conjecture. However there is a scarcity of research on the subject. Indeed most practising Engineers still rely on Skepmton’s 1956 paper, which was based on London clay, for guidance. Modern techniques have undoubtedly increased this factor.

Consequently savings could be made if appropriate investigation is carried out. Testing should also be done in different geological areas than London to establish if alpha is significantly related to the mineralogy of the clay or purely the drilling techniques employed.

Displacement flight auger systems

The prevalence of displacement flight auger systems is on the increase as clients seek to limit increasing spoil removal costs. In inner city sites traditional driven methods of displacement pile construction are not possible due to the damage vibrations can cause so displacement augers are seen by many as the best alternative.

Problems with the development of these systems have dogged the industry in recent years. Rock and Alluvium are looking for a system or range of systems that will work in a variety of ground conditions.

New design approach for chalks

Ciria’s latest report in to piling in chalk, C574, and its supplement for the calculation of shaft friction for CFA piles still, according to many Engineers, gives unsatisfactory answers to the problem of designing piles in this extremely variable material.

The Research Engineer would be given the task of evaluating existing design methods and if necessary he would carry out full scale testing to help develop and prove a new theory.

Lime piles

The use of lime cement columns for ground stabilisation in the UK is still in its infancy but could potentially grow and take a share of the bored pile market. Rock and Alluvium are considering entering this market and need a feasibility study to be carried out in order to access risks, costs and to help produce method statements.

Baxter, D. ... et al. (2008). Refining shear strength characteristic value using experience. Proceedings of the Institution of Civil Engineers - Geotechnical Engineering, 161 (5), pp. 247 - 257

Baxter, D. ... et al. (2011). Discussion: Refining shear strength characteristic value using experience. Proceedings of the ICE - Geotechnical Engineering, 164 (4), pp. 289 - 291. https://dspace.lboro.ac.uk/2134/17258


Baxter, D. ... et al. (2008). Using Experience And Case History Data To Enhance The Design Of Piled Foundations And Predict Behaviour Characteristics, Proceedings of the 6th International Conference on Case Histories in Geotechnical Engineering, Arlington VA, 11th-16th August.

Baxter, D. ... et al. (2008). Bored Displacement Piles In Stiff Clay: construction and performance, Proceedings of the 2nd BGA International Conference on Foundations, Dundee, 24th -27th June.

Baxter, D. ... et al. (2006). The Design And Formation Of Bored Displacement Piles - A United Kingdom Perspective, Proceedings of the 10th International conference on Piling and Deep Foundations, Amsterdam, 31st May – 2nd June, pp210-218.



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+44 (0)1509 222623

The Centre Administrator
Loughborough University
LE11 3TU

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